Integrated multiuploaddialog into MODx core
Replacing old uploaddialog code with new multiuploaddialog code
Integrated multiuploaddialog into MODx core
Replacing old uploaddialog code with new multiuploaddialog code
Revert "Replacing old uploaddialog code with new multiuploaddialog code"

This reverts commit 271b721d16c22b00873198cc065544c2d8e1dcd6.
Keep old UploadDialog for BC, support for setting 'permitted_extensions'.
Use new MultiUploadDialog
Merge conflicts from reverting a commit
Replaced uploaddialog with more modern multiuploaddialog

* origin/pr/11253:
  Use new MultiUploadDialog
  Keep old UploadDialog for BC, support for setting 'permitted_extensions'.
  Revert "Replacing old uploaddialog code with new multiuploaddialog code"
  Replacing old uploaddialog code with new multiuploaddialog code
  Integrated multiuploaddialog into MODx core
  Replacing old uploaddialog code with new multiuploaddialog code
  Integrated multiuploaddialog into MODx core

Conflicts:
	_build/templates/default/sass/index.scss
	core/lexicon/de/file.inc.php